My guess is that the problem is the call to Printer_Init(). Based on a little code scanning and grepping, and on the default wxagg plot with toolbar, I don't see that any of the Print* stuff is being used by mpl--but I know very little about wx, and I have not looked deeply into backend_wx*.
Can we simply remove Printer_Init() from FigureCanvasWx.__init__, or will that have dire consequences for someone? Is there a wx wizard who can provide a good solution?
One way or another, I would like to get this ancient ticket closed.